Web Services for Digital Library Construction T Hickey

Web Services for Digital Library Construction T. Hickey Indo-US Workshop June 2003

What are Web Services? • Machine-to-machine communication • Run over standard Web protocols – XML syntax, HTTP packaging • Several approaches – REST • Representational State Transfer – SOAP • Simple Object Access Protocol

REST • REST is simplest – Send an HTTP request – Get back a response (XML, HTML) – Examples • Web browser • Open. URL • Z 39. 50 as a Web service: SRU http: //sfx. bath. ac. uk/sfxmenu? genre=book&isbn=1234 -5678 http: //www. kb. nl/ cgi-zoek/srw. pl? query=test&max. Rec=10&rec. Schema=dc_record

SOAP is more complex • Simple Object Access Protocol • Z 39. 50 as a SOAP service: SRW – http: //www. loc. gov/z 3950/agency/zing/srwu /wsdl/zing_srw_binding. wsdl • WSDL • UDDI

A set of Web services for the digital library • • Register Search Resolve Navigate Decompose Enhance Transform Skip to examples

Registration Services • Metadata about metadata – Dublin Core extensions – Digital format descriptions • Metadata about objects – Books – Web resources • Metadata about agents – People – Institutions

Search Services • Go from data to links – Name to preferred form – Search terms to record list

Resolution Services • From links to data – Record numbers to records – Controlled names to name metadata – Class number to textual description

Navigation Services • Movement within hierarchies – Classification, e. g. DDC – FRBR (work, expression, manifestation, item) • General network movement – Link selection and following

Decomposition Services • • • DDC Numbers Names within a list Citations within a paper Structure of a document Letters within an image

Enhancement Services • Normalization – Linkage to registered forms • Addition of DDC numbers • Authority control on agents • Content augmentation – Add information to a brief record from a matching longer record

Transformation Services • Syntax translation – MARC 21 to MARC XML • Semantic translation – Qualified Dublin Core to MARC 21 – Library of Congress SH to FAST • Content translation – English to French?

Examples of Web Services • XISBN service – Maps ISBNs to ISBNs • Open. URL Registry – Provides names and definitions for Open. URL services • GSAFD Thesaurus

The XISBN Web Service Amazon User FRBRized ISBN Server Library

On Amazon

Cornell University

Open. URL Registry • OAI-PMH Registry – http: //purl. org/openurl/ – OAI implies XML delivered • But, stylesheets can produce – HTML display – Web browser user interface

GSAFD as a test case • Enhanced subject authority records for genre terms are now available via the OAICat framework. This development is a result of the combined efforts of the OAICat project and the Terminology Services project. The enhanced authority file is a version of the MARC 21 authority records for GSAFD genre terms. The enhanced version of the file has the following features: – The content of the file is MARC XML – Established terms in the file are accessible via a URL – Established terms in the file are mapped to equivalent Library of Congress Subject Headings (lcsh) and Library of Congress subject headings: Annotated Card Program (lcshac) (i. e. , LC Children’s heading) – Authority records can be displayed in MARC or in a thesaurus-style display – The file is also accessible via SRW/SRU under the Zthes protocol